Greenhead K&B .29

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Greenhead K&B .29

Postby taildragger-j3 » Wed Jun 13, 2007 2:56 pm

I have acquired an OLD K&B Greenhead .29 that I think I'm going to put on a RSM Ringmaster I'm building. I've run a partial tank of fuel through it on a test stand and I think it will be OK. I'm pretty sure It's been a while since this baby has been run, but it seems to have good compression, etc.

A couple of questions.

1. Suggestions for a prop. I ran it with a 9X4 and it seemed to do OK. I was thinking an 8X4 might let it turn up a little. It's my recollection that Torps like to wind up.

2. It has a restrictor in the venturi. Should I pull it out and let it breathe more, or leave it in?

Thanks guys
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Postby gossie » Wed Jun 13, 2007 4:16 pm

A 9x4 prop. is about right for freeflight use, but for controline should think you need to up the pitch and reduce the diameter. Maybe an 8x6, 8x7 or 8x8?

For contoline I would leave the restrictor in for sure, so the engine sucks stronger to give a more consistant run. :)
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Greenhead K&B 29

Postby Ken McClenahan » Wed Jun 13, 2007 8:39 pm

Use a 10x5 prop (best) or a 9x6 prop. A 9x4 is way to small (the right size for a 19).
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Postby Jim Thomerson » Thu Jun 14, 2007 12:56 pm

Yes, a 10 x 5 or a 9 x 6 is about right. If you take the restrictor out, you wll need to run pressure go get adequate fuel feed. Do run a fuel with a good amount of castor oil, at least 25% total oil.
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Postby walt » Fri Jun 15, 2007 5:51 pm

I used to use a 9 x 6 or 7 on my old steelfin Veco 29 in an original Super Clown. Plenty of pull. I think the Veco 29 and Torp 29 were very similar. At least the early ones were. Used a 10 inch prop, don't remember the pitch, on my Torp 29 ignition engine flying a Zipper FF. Great power/plane combo.
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Postby chiefss » Sun Sep 30, 2007 1:40 pm

An 8x4 is a 15 size prop and a 9x4 is a 19 size prop. A 29 can use a 10x6 or a 9x7 and down to a 9x6 or 10x5 with good results.
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